Hydraulic press



Feb. 11, 1958 E. c. PINSENSCHAUM 2,322,822

HYDRAULIC PRESS I Filed April 15, 1954 4 Sheets-Sheet l FIG.I

- INVENTOR. EDWIN 0. PINSENSOHAUM 1953 E. c. PINSENSCHAUM $822,822

v HYDRAULIC PRESS Filed April 15, 1954 4 Sheets-Sheet 2 PIC-3.3

FIG.2 fnllll INVENTOR. EDWIN 0. PINSENSCHAUM BY @045 KW 1958 E. c. PINSENSCHAUM 2,822,822

HYDRAULIC PRESS Filed April 15, 1954 4 Sheets-Sheet 3 IN V EN TOR.

. EDWIN 0.PlN$EN$Ol-IAUM Feb. 11, 1958 E. c. PINSENSCHAUM 2,822,822

HYDRAULIC PRESS 4 Sheets-Sheet 4 Filed April 15, 1954 97 FIG.5

United States Patent HYDRAULIC PRESS Application April 15, 1954, Serial No. 423,462 2 Claims. (Cl. 137-6225) This invention relates generally to hydraulics and is more particularly directed to hydraulically operated machines such as presses and control mechanisms therefore.

An object of this invention is to provide a press of simple, compact construction which will have a hydraulic ram and control mechanism capable of causing a complete cycle of operation of the ram following an initial actuation of a manual control element.

Another object of this invention is to provide a selfcontained hydraulic press having a power driven hydraulic pump, a hydraulic ram and novel control mechanism between the pump and the ram, such control mechanism having a flow directing spool valve normally urged by resilient means toward a position to direct fluid from the pump to the ram to tend to urge it in one direction and responsive to another suitable power means to move to a second position to direct fluid from the pump to another part of the ram to cause it to move in a selected direction, means being provided in connection with the control mechanism to utilize fluid exhausted by the ram while moving in the selected direction to retain the spool in position to continue ram movement in such direction, the resilient means returning the valve spool to its first position to cause the return movement of the ram when the ram ceases to move in the selected direction irrespective of the distance moved or the cause of the interruption of movement in the selected direction.

A further object of this invention is to provide a control valve mechanism for a hydraulic ram, such control valve mechanism having a casing with ports connected with a source of fluid pressure, the opposite ends of the ram cylinder and exhaust and a valve spool for selectively establishing communication between one or the other of the cylinder ports and the fluid pressure inlet and the other cylinder port and exhaust, the valve mechanism also having a piston associated with the valve spool and exposed to fluid flowing from one of the cylinder ports to exhaust so that some of the force of the exhaust fluid will be utilized to retain the valve spool in position to cause the ram to continue moving in a predetermined direction until it travels a desired distance or has exerted a pressing force of desired magnitude on an article of work.

-It is a still further object to provide the valve mechanism mentioned in the preceding paragraph with electroresponsive means in the nature of a solenoid for moving the valve spool to one of its positions to initiate the movement of the hydraulic ram in one direction and spring means for moving the valve spool to another of its positions to cause return movement of the ram, the piston responsive to the exhaust flow being utilized to prevent movement of the valve spool by the spring until movement in the desired direction has been terminated.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of embodiment of the invention is clearly shown.

2,822,822 Patented Feb. 11,1953

In the drawings:

Fig. 1 is a vertical sectional view taken through a press formed in accordance with the present invention.

Fig. 2 is a rear elevational view of the press shown in Fig. l.

Fig. 3 is a diagrammatic view of the hydraulic system employed in the press, the valve and the power cylinder being shown in section.

Fig. 4 is a view similar to Fig. 3 with the valve parts and the piston and ram of the cylinder being shown in diflferent positions than in Fig. 3. I

Fig. 5 is also a view similar to Fig. 3 with a diagram of the electrical circuit used in the press also being shown; this figure also shows, in section, a relief valve employed in the hydraulic system.

Fig. 6 is a vertical sectional view taken through the relief valve shown in Fig. 5 showing the valve in position to direct the'excess fluid under pressure to exhaust.

Referring more particularly to the drawings, the numeral' 20 designates a press which includes the features of the invention. This press is of the 0 frame type and includes a cast or otherwise formed frame 21 having a As the pump 31 forwardly extending base section 22, an upwardly extending body section 23 and a head section 24 extending forwardly over the base section. The frame is formed to provide a fluid reservoir 25 in the base section, this reservoir having a top wall 26 adjacent the lower end of the body section 23. This wall 26 has a relatively large opening 27 formed therein.

The base section of the press is provided with a power cylinder 28 having a ram 29 which moves upwardly into the space between the base and head sections 22 and 23. The top wall of the forwardly extending portion of the base section 22 has a relatively great thickness, the cylinder 28 being secured to and supported thereby. The opposing bottom wall of the head section 24 is formed with an opening 30 for the reception of suitable tooling (not shown) which may be used with the press. For operating the power cylinder 28 to cause the ram 29 to move into and out of the space formed between the head and base, there is provided a hydraulic pump 31 which is driven by an electric motor 32. These elements are carried by a mounting plate 33 secured to the upper side of the top wall 26 of the reservoir. The plate 33 has a pump supporting bracket 34 extending therefrom through the opening 27 into the reservoir 25. The pump 31 is secured to this bracket and its shaft 35 is coupled at 36 to the shaft of the motor 32. The plate 33 also supports a manifold block 37 in which certain passages are formed, this block 37 having a control valve mecha-' nism, indicated generally by the numeral 38, secured thereto.

The block 37 (see Fig. 5) is formed with a pair of vertical passages 40 and 41 and horizontal passages 42 to 45, inclusive. Passage 42 is arranged to connect with a horizontal passage in the valve body 46 e which leads to a groove 47 extending annularly around a vertical bore 48 formed in the body. Similar annular grooves 50 and 51 are arranged one on each side of the groove 47 and these grooves connect with angularly extending passages 52 and 53 which communicate respectively with passages 43 and 44. Passages 43 and 44 are connected by pipes or tubes 54 and 55 with the lower and upper ends, respectively, of the power cylinder 28. The lower end of the bore or passage 40 in the block 37 is con-v nected by a conduit 56 with the outlet of the pump31. operates, fluid will be drawn from the reservoir 25 and delivered through the passage 40 to I horizontal passage 42 and then to the groove 47 of the valve. A valve spool 57 is disposed in the bore 48 to establish communication between certain of the grooves in" the valve body depending upon the position of the valve spool. In Fig. 3, the valve spool 57 is shown in its normal position to which it is urged by a coil spring 58. This spring 58 is arranged in a chamber 60 formed by a ,cap 61 securedto the lower end of the valve body 46. Thelchamber 60 is connected with the lower end of the valve bore 48 and is also connected by a conduit 62 with the reservoir 25. Coil spring 58 abuts a washer 63 disposedin the cap 61 for this purpose. The coil spring also abuts a shoulder 64 formed on a cap 65 which is pinned or otherwise secured to the lower, end of the valve spool ,57. t This cap, in addition to serving as an abutmerit for the spring 58, closes the open lower end of a passage 66 formed axially in the spool 57, thispassage being intersected at spaced points by laterally extending passages 67 and 68 ,formedin the spool. The purposes of these passages will appear from the following description.

The cap 65 also serves a third purpose since it provides an abutment which is engaged by a piston 69 disposed for sliding movement in the chamber 60. This piston divides the chamber 60 into inner and outer sections 70 and 71, respectively, the piston being provided with a packing 72 and one or more orifice elements 73 which establish restricted or limited communication between the inner and outersections 78 and 71 of the chamber 60. The transversely extending passage 68 registers with an external annular groove 74 formed in the spool 57. A second external groove 75 is provided in the spool 57 in spaced relation with the groove 74.

It will be seen from Fig. 3 that, when the valve spool 57 is normally positioned, the groove 75 will establish communication between the groove 50 and another groove 76 formed in the valve body. As shown by dotted lines in Fig. 5, groove 76 is connected with the horizontal passage 45 in the manifold block 37, this passage connecting with vertical passage 41 which in turn is connected' by conduit 77 with the reservoir 25. Also when the valve spool 57 is normally positioned as shown in Fig. 3, the groove 74 in the spool establishes communicationbetween grooves 47 and 51, the latter being connected as shown in Fig. 5 with horizontal bore 44 in manifold block 37 and by the conduit 55 with the upper end of the power cylinder 28. Fluid under pressure from the pump 31 will thus be conducted to the upper end of the power cylinder 28 and will exert its force on the upper surfaceof the piston 78 which is disposed for reciprocatory movement in the cylinder element of power cylinder 28. Piston 78 is connected with the ram 29 andserves to impart movement thereto. In the normal position of the valve spool 57, the ram 29 and piston 78 will be urged to the retracted position as shown in Fig. 3. When the piston 78 is fully retracted, the space at the upper side of the piston will be connected with the space at the lower side by a passage 80 containing a spring pressed check valve 81. This check valve serves to unload the pump 31 when the ram and piston are fully retracted by permitting fluid to by-pass the piston 78 and return through the'control valve mechanism 38, to reservoir 25.

The manifold block 37 has a relief valve body 82 fastened to its upper end, the body 82 having a passage 83 communicating with the vertical passage 40 and a chamber 84 registering with the passage 41. This chamber 84 is connected with the passage 83 by a horizontal passage 85, the body 82 receiving a valve seat insert 86 between the passage 85 and the lower end of the body 82. This insert rests against the top surface of the manifold block 37 when the body 82 is secured in place there on. The insert 86 has an opening extending therethrough to establish communication between the chamber 84 above the seat and the bore 41 which is connected with the reservoir. The seat 87 in the insert 86 is normally engaged by a poppet valve 89 formed integrally with a piston 88 disposed for sliding movement in the chamber 84. This piston divides the chamber into inlet and control pressure sections or zones 90 and 91, the latter being above the piston 88 and communicating with the inlet pressure section through a restricted passage 93 formed in the piston 88.

When the pump 31 is in operation, fluid under pressure therefrom will occupy the passages connected with the outlet port of the pump, fluid at the same pressure occupying the spaces above and below the piston 88 by reason of the passage 93. The piston 88 has a second passage 4 which establishes communication with the opening in the valve seat 87 and the control section or zone 91 above the piston. This communication is interrupted, however, under normal conditions by a pilot valve 95 also received for sliding movement in the relief valve body 82. The pilot valve 95 is urged into engagement with the upper side of the piston 88 by an adjustable coil spring 96 contained in the relief valve body, the tension of this spring being varied by an adjusting screw 97. The body of the pilot valve serves as a piston, this piston being exposed at one end to the pressure in the control pressure section or zone 91.

The construction and operation of the relief valve is substantially the same as that shown in Patent No. 2,619,112 issued November 25, 1952, to Wendell E. Renick. When the pressure in the control pressure section or zone 91 exceeds a predetermined value, pilot valve 95 will be urged in an upward direction in opposition to the force of spring 96. Fluid may then flow from the control pressure section or zone 91 through the passages 94 and 41 and conduit 77 to the reservoir 25. When the valve opens sufiiciently, the fluid pressure in the control pressure section or zone 91 will drop permitting piston 88 to move in an upward direction causing valve 89 to move away from its seat 87. The inlet pressure section or Zone 99 will then be connected directly with the reservoir 25 and excess fluid will be exhausted to the reservoir. When suflicient fluid has been exhausted to substantially equalize the forces on opposite sides of the piston 88 and reduce the pressure in the control section or zone 91 sufiiciently to permit spring 96 to return the pilot valve 95 into engagement with the piston 88, the valve 87, 89 will close interrupting the flow of fluid to reservoir 25 or exhaust. Fluid pressure is built up in the pressure section of the hydraulic system when the ram 29, during its upward movement, engages an obstruction which offers sufiicient resistance to movement of the ram'to'cause the pressure to increase.

The ram is caused to move in an upward direction by moving the valve spool 57 to its lowermost position in which it is shown in Fig. 4. The spool is moved in a downward direction 'by a solenoid, indicated generally in Fig. 5 of the drawing by the numeral 98, secured to the upper end of the valve body 46. This solenoid is of conventional construction and, when energized, serves to move the valve spool 57 in opposition to the spring 58. The solenoid is controlled by a pair of push-button switches arranged in the circuit therewith. These push-button switches are located on the forwardly projecting portion of the base section 22 of the press frame. They control the closing of a circuit 101 containing the solenoid 98 and connecting with the supply lines 182 for the electric motor 32. When the push-button switches 180 are closed, the solenoid 98 will be energized causing the valve spool 57 to move to the position shown in Fig. 4.

When valve spool 57 is in the position seen in Fig. 4, the groove 75 in the valve spool establishes communication between the'gro'oves 47 and 50 and thus connects the pump 31 with the lower end of the power cylinder. Fuil-cl pressure from the pump will then be applied to the under side of piston 78 causing the piston and ram to move in an upward direction. in so moving, piston 78 causes fluid to be discharged from the upperend ofthe power cylinder 28, this fluid flowing through conduit 55, passages 4'4 and 53 to groove 51. When the valve spool 57 is disposed in its lowermost position as shown in Fig. 4, groove 51 is connected by passages 68, 66 and 67 with the inner section 70 of the chamber 60. Fluid flowing to this section 79 of the chamber 60 will flow through the restricted passages 73 to the outer section 71 of the chamber 60 and through the conduit 62 to the reservoir 25. Since passages 73 are restricted, fluid flowing therethrough will create a pressure diflerential which will be efiective to apply a force tending to urge the piston 69 in a downward direction. This force acting on piston 69 will overcome the force of the spring 58 and the valve 57 will be retained in its lowered position until exhaust flow from the upper end of the power cylinder 28 is terminated. This flow may be terminated through the engagement of piston 78 with the upper end of the cylinder 28 or if the ram should engage an obstruction offering sufficient resistance to overcome the force exerted by the fluid pressure on the piston 78.

After the ram 29 engages an obstruction, the force exerted by the ram will increase as the pressure on fluid under the piston 78 increases. When this pressure increases sufliciently to cause the relief valve 89 to move to an open position, which will quickly occur due to the relative incompressibility of the oil, the maximum pressure for which the relief valve has previously been set will be generated by the pump and the ram will then be exerting the tonnage desired. When the ram 29 stops moving and exhausting of fluid from the power cylinder 28 is discontinued, the spring 58 will move the spool 57 in an upward direction, the fluid in the inner section 70 of the chamber 60 being expelled through the restricted passages 73. The spool will then be moved to the position shown in Fig. 3 in which the pump 31 which forms the source of fluid pressure is connected to the upper end of the power cylinder 28 while the lower end thereof is connected with the reservoir 25 or exhaust. The ram and piston of the power cylinder will be returned to a retracted position and the cycle of operation will then be completed.

It will be obvious from an inspection of Figs. 4 and 5 that, when the switches 100 are retained in a closed position, the solenoid 98 will remain energized and will hold the spool 57 in its lowermost position in which the fluid pressure source is connected with the lower end of the power cylinder. The ram will then remain in an extended position even though exhaust fluid flow has been discontinued. As soon, however, as the switches 100 are opened, the spool valve 57 will return to its elevated position causing the retraction of the ram.

Fig. 5 shows a pressure gage 103 connected directly to the upper end of the passage 83. In Figs. 1 and 2, this pressure gage is shown in position in the front wall of the head section of the press. It is connected by a conduit 104 with the passage 83, the showing in Fig. 5 being merely diagrammatic.

From the foregoing, it will be observed that a simple, compact, self-contained press has been provided and that a minimum of attention will be required to maintain the press in operating condition. The fluid pressure generating unit is carried completely by the plate 33 and may be assembled prior to installation in the press frame.

While the form of embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

I claim:

1. A hydraulic cylinder control valve mechanism comprising a casing having a longitudinally extending bore and inlet, first and second cylinder and exhaust ports spaced longitudinally thereof; spool means disposed for movement in said bore, said spool being operative in a first position to establish communication between said inlet and said first cylinder port and between the second cylinder port and an exhaust port; resilient means tending to urge said spool means toward said first position; means for moving said spool means in opposition to said resilient means to a second position in which said spool means establishes communication between said second cylinder port and said inlet port; means forming a chamber at one end of said bore, said chamber having an exhaust port at one end; a piston engaging said spool and dividing said chamber into inner and outer sections, said spool forming a passage operative in the second position of said spool to establish communication between said first cylinder port and the inner section of said chamber, the outer section of said chamber communicating with said exhaust port; and means forming a restricted passage establishing limited communication between the inner and outer ends of said chamber, fluid flow from the inner to the outer end through said passage creating a pressure differential which causes said piston to restrain said spool against movement by said resilient means.

2. A hydraulic cylinder control valve mechanism comprising a casing having a longitudinally extending bore and inlet, first and second cylinder and exhaust ports spaced longitudinally thereof; spool means disposed for move- .ment in said bore, said spool being operative in a first position to establish communication between said inlet and said first cylinder port and between the second cylinder port and an exhaust port; resilient means tending to urge said spool means toward said first position; means for moving said spool means in opposition to said resilient means to a second position in which said spool means establishes communication between said second cylinder port and said inlet port; means forming a chamber at one end of said bore, said chamber having an exhaust port at one end; a piston engaging said spool and dividing said chamber into inner and outer sections, said spool forming a passage operative in the second position of said spool to establish communication between said first cylinder port and the inner section of said chamber, the outer section of said chamber communicating with said exhaust port; and said piston forming a passage establishing limited communication between the inner and outer ends of said chamber, fluid flow from the inner end of said chamber through said passage creating a pressure differential which causes said piston to restrain said spool against movement by said resilient means.

References Cited in the file of this patent UNITED STATES PATENTS 2,448,532 Kirkham Sept. 7, 1948 2,448,557 Stephens Sept. 7, 1948 2,541,958 Deardorfl Feb. 13, 1951 2,615,433 Deardorfl Oct. 28, 1952 2,638,122 Ludwig May 12, 1953 2,645,488 Bugg July 14, 1953 2,661,766 Adams Dec. 8, 1953 

